The Science Of Murder
by Yuuki-Neechan
Summary: A collection of oneshots that uses physics to murder people.
1. Chapter 1

The Science of Murder

Beta: Stazzles-Otouto

Kinematics

This was a rare occurrence, Mouri Kogoro, Mouri Ran and young Conan-kun had been invited to a crime scene, rather than having been a witness. Seeing a crime scene from an observers perspective instead of an inside source was quite a novel experience for all three of them.

"Why are you here brat?" Mouri moaned as Conan followed behind him towards the police officers, followed dutifully by Ran.

"Because Conan-kun sometimes see's things that you don't because he's small and is able to notice things that are low down and hidden; places where tall people never look" Ran said with a smile at her little charge "plus, he knows not to mess with the crime scene"

"Also, it's fun to see you work uncle" Conan chipped in with his most innocent voice. Mouri grumbled a bit before they reached the officers clustered at the edge of the road next to a broken bridge.

"Ahhh Mouri-san" Megure-keibu said as he saw the approaching man,

"Keibu-dono, you called for my assistance?" Mouri said in his most professional voice.

"Yes, as you may have seen on your way down the road there is a sign that tells all drivers that the bridge ahead is broken and there is a right-turn diversion down to the next bridge" Megure started, pointing to the bridge behind them that was indeed broken. "The road sign is about 130 metres away from the bridge to give the drivers ample time to slow down so they can turn even when going at the speed limit of 60 mph"

"132 metres keibu" Takagi said, appearing at their side and winding up a large reel of measuring tape.

"Ahh thank you Takagi" Megure said

"Why are you telling us this?" Ran asked, confused at the apparent unneeded details.

"Well, this is relevant to the crash Ran-kun" Megure said kindly "The driver of the crashed vehicle was Fukane Aoji, 21 year old male who was apparently driving home from work at 5am this morning from his job as a night guard at the Beika Museum. The speed camera at the corner clocked his speed at 67 mph, 7 mph over the limit, if he had not been speeding we would not have known his speed at all which would not have caused all this confusion"

"Confusion?" Conan asked

"Yes Conan-kun, Fukane-san should have seen the sign and been able to slow down and turn for the diversion but he did not, there are skid marks on the road to show that he pressed the brakes very sharply and going at 67 mph he should have been able to come to a complete stop in about 70 metres, but the thing is he didn't start braking until he was 81 meters away from the bridge and therefore should have stopped about 10 metres before the bridge, yet he didn't."

"And you can't work out why it took him a long time to start braking or why the skid marks are so long?" Conan asked, "Maybe there was something wrong with the brakes?"

"The car has been retrieved and there are no signs of tampering" Takagi reported. Conan wandered off while Mouri asked more about the man.

"_Car stopping distances compose of two things; one is the braking distance of the car itself, and the other is the thinking distance of the driver. In other words, how long it takes the driver to see an obstacle and push the brakes, the reaction time…if the car was travelling at 67mph which is 30 metres a second, and the average reaction speed for a young male is 0.65 seconds it would make a thinking time of 19.5 metres in an average mass car of 900kg. But he was exactly 51 metres past the sign before he began braking, so where did the extra 31.5 metres come from?...The average braking distance for that speed would be 70 metres, 72 if I am exact so he should have been able to stop just before the bridge…" _Conan pondered as he wandered around the site which had been cordoned off by the police. _"The questions are: why did he brake so sharply? Why didn't he slow down right after he saw the sign? And where did the extra 31.5 metres go?" _Conan wandered over the bridge and looked down into the shallow river below. The car wouldn't have even been fully under water at the depth of the river, the water would have only come up about half way.

"If the brakes were definitely working fine then why did he take so long to use them? Was his thinking distance affected in some way, maybe by drugs?" Conan wandered in a roundabout way until he came to the forensic officers

"Ne, did Fukane-san have any drugs in his system?" Conan asked sweetly.

"That's what we thought too at first, that Fukane-san might have been on drugs but there are no traces of such a thing in his body" the officer said before they turned away and continued taking pictures of the area.

"_For Fukane-san to have a thinking distance of 51 metres at his speed his reaction time would have had to have been 1.70 seconds, that is an oddly slow reaction speed, but there were no drugs in his system that could have slowed his reactions" _he mused as he walked over to the skid marks, he inspected them closely, they seemed to get heavier in places, suggesting that the driver had pressed the brakes hard and then lifted his foot slightly and pressed down again multiple times.

"Why would someone do that?" Conan asked aloud as he walked along beside the marks, "Fukane-san lifted up and pressed his foot down on the brake five times by the look of these markings, it's almost like he wasn't concentra-" Conan stopped mid monologue. He ran over to the forensic officer again. "Ne did Fukane-san have a head injury?" he asked quickly, the officer looks at him

"Yes he did, most likely sustained when the car went over the bridge. It was on his forehead so we assumed it was from an impact with the steering wheel" the officer said

"So there isn't any chance he had a head injury before the accident?" he asked, trying to phrase it innocently. The officer and surrounding officers stopped to look at him.

"Why do you say that Conan-kun?" the officer asked

"Well because the marks are inconsistent, like Fukane-san didn't apply the same pressure on the brake the whole time which shows he wasn't concentrating and a head injury would have also slowed his reaction time, which would explain the long distance before he started braking" Conan explained, he looked up at the slack-jawed officers before scratching his head and laughing childishly "at least that's what they said in the hospital programme I was watching the other day, they brought in a woman with a concussion and were talking about how she couldn't concentrate and had slow reactions to what people were saying to her, isn't it sort of the same situation?" he asked, the officers grinned at each other and patted the boy on the head.

"Very smart Conan-kun, I would never have thought of that, a head injury would explain all the oddities of this case. I'll just call the morgue and find out if the head injury was there before the crash or caused by it" the officer turned away and pulled out a phone. Conan took the chance to go back to Megure-keibu. He listened to the officer in silence while waiting for the forensic officer to get his answers, if he was lucky he wouldn't need to knock Mouri out for a deduction show. The confirmation came five minutes later and the officer ran over to Megure-keibu from the bridge.

"Megure-keibu" the forensic officer huffed "Conan-kun was right, Fukane-san had a head injury from before the accident, that's why it took him a long time to brake, the morgue workers also noted that he had blood on his shoes which hadn't quite been washed off in the water after he went over the bridge, it could have caused his foot to keep slipping off the break pedal which explains why the marks on the road are inconsistent."

"Well that explains that, but why did he have a head injury and blood on his feet?" Megure-keibu asked the officers at large. The officers at large stayed silent and Conan silently groaned before putting on his childish voice again

"Ne ne, Keibu-san, wouldn't that mean that he was attacked and got blood on the floor then stood in it while running away?" Conan asked cutely.

"It could do Conan-kun, it would also explain why he was speeding, and his concussion couldn't have been that bad if he could still coordinate driving a car." Megure-keibu said, smiling genially at him. Takagi gave Conan a grin,

"Good job Conan-kun, you always seem to know the right things to say" Takagi said with a glint in his eyes, Conan laughed nervously while Megure-keibu spoke over Conan's head to Mouri.

"Thank you for your assistance Mouri-kun, but I think that from now it is just a matter of finding the cause of Fukane-san's head injury. Takagi will drive you home."

"Thank you Keibu-dono, can you call and tell me what happened after the case is closed?" Mouri asked, seeming to have a genuine interest.

"Yes oh course Mouri-kun" Megure-keibu said and shook hands with him, bowed to Ran and left with a friendly smile at Conan. Takagi ushered them over to a squad car and they left the scene.

The car ride home was an awkward affair, Ran and Mouri talked to each other about the case, oblivious to the silent Conan who was busily trying to avoid Takagi as the officer frequently tried to catch his eyes in the mirror. The journey finally ended and they got out of the car and waved Takagi off before retreating inside. Conan went to his room straight away and pushed the button on the side of his glasses to activate the microphone he had planted in Takagi's pocket. There was just the sound of the car as Takagi drove in silence, presumably back to the Police Headquarters, soon enough the car engine died down and new sounds echoed down the microphone of chatter and walking.

"_Oh Takagi-kun, how did it go?" _said a woman's voice,

"_Ah, Satou-san, it went fin, Megure-keibu is going to Fukane-san's work now to find out what happened, turns out he had a concussion before the accident which was why he crashed" _Takagi answered, sounding quite happy.

"_They figured that out fast, Conan-kun I presume?" _Satou asked

"_Yes, and I won the bet, it took him 7 minutes and 22 seconds until he got that look on his face a went over to one of the officers" _Takagi said while Satou groaned,

"_It sounded like a difficult case, that's why everyone else bet over 10 minutes" _Satou huffed.

"_Ahh you shouldn't underestimate Conan-kun, that kid is special. It's rumoured that Kudo Shinichi taught him everything he knew about being a detective before he vanished." _Takagi told her as their footsteps walked down another hall and into a noisy room.

"_Listen up everyone!" _Satou shouted over the din _"Takagi-kun won, it was under 10 minutes" _This was greeted by the sound of collective groans and the sounds of paper, most likely money. Conan shut off the microphone and sat down on his bed, sighing. If they were betting on him then they must not be bothered by his blatant disregard for the age: intelligence ratio, although the theories that he was so smart being because of his older self may prove to be problematic in the future. Conan flopped back onto the bed and threw an arm across his eyes,

_Let them have their fun…as long as they don't start telling everyone that 'Conan' got taught by Kudo Shinichi then the Black Org should take no notice…hopefully. Best not tell Haibara about this, I wouldn't want her to panic. _

Mouri got a phone call a day later from Megure-keibu. The other night guard at Fukane-san's work had been arrested, the lot where Fukane-san normally parked his car had been covered in blood and the other guard, Kenichi, had been found trying to scrub the blood away. From what Kenichi said, he had hit Fukane-san over the head in an attempt to kill him but only knocked him out and he left him to go find some rope only to find him gone when he came back. Kenichi had apparently been so angry at Fukane-san for all his "snide remarks about me and my family" that he had snapped. Megure-san told Mouri that he was seriously debating getting Kenichi put into a mental ward; it seemed that Kenichi had anger issues and had attacked many of the officers in the 24 hours he had been incarcerated.

_If he is committed to a mental ward it will be as good as a prison and may even help him. _Conan thought as he helped Ran set the table for dinner. Just as the three of them were about to sit down the phone ran, Mouri went to answer it.

"Moshi Moshi, Mouri Kogoro speaking...Ahhh Keibu-dono...yes of course I will…the squad car is on its way already?...okay I'll be there shortly… sure I'll bring the brat if you want me too…yes…yes goodbye" Mouri turned around to face them.

"Another case?" Conan asked.

* * *

**A/N: Hope you enjoyed reading it, this one shot is part of a collection I will be writing over the next few months to help me with my physics. I will put all the one shots in the same story as different chapters so I don't overcrowd my profile. Thank you for reading and I hope the physics aspects of the chapter made sense. :D**


	2. Chapter 2

The Science of Murder

Beta: Pandaeyes

Electricity

Ran dragged Conan by the hand as she wandered around the halls of the university, a map in her hand.

"Do you know what University course you want to take in two years Ran-nee-chan?" Conan asked as he jogged a little to keep up with her harried stride.

"I know I don't even have to choose until next year but I really don't know what I want to do Conan-kun" Ran said agitatedly as she consulted the campus map again.

"Then why don't you look at everything?" he suggested.

"We don't have time to do that!" Ran told him. She stopped mid stride as they came to a fork in the hallway.

"I have an idea, why don't you look at all the ones that you find interesting first and then if you have time at the end look at some other ones" Conan proposed, "These open days are happening all week and you don't even need to be looking until next year so you can look at the ones that interest you now and then you have a whole year to decide if you want to do the subject or not and if you don't you can come to next year's open day." Ran stopped and looked down at her little charge before picking him up and hugging him tightly,

"That's a great idea, thank you Conan-kun. I knew bringing you would be a good idea!" Ran said and placed him on the floor again, "Right, the nearest one to this corridor that looks interesting is English" she said confidently and took Conan's hand again, leading him down the left fork.

Ran led Conan through every mainstream subject first, lingering on English and Japanese History departments for the longest time before moving on to the more specialist subjects. They were walking through the physics area when a chattering drew their attention, the noise was coming from a room to their left that had a sign on the door 'Degree's in Electrical Safety'.

Curious Conan walked into the room to see that a huge electrical circuit board dominated the room, but the guests couldn't go near it due to a metal barrier that cut the room in half, with the audience near the door and the circuit board in the other half with three male undergraduates.

"Okay, let's start with introductions. I'm Hayato Tsuma" said the first man; he had brown eyes and black hair that was dyed blue at the ends.

"I'm Jouro Katashi, Nice to meet you all" said the second man; he had almost black eyes, black hair and a blank expression.

"Chris Wiltshire" said the last man; he was obviously not Japanese and had spiky brown hair and bright green eyes, he smiled brightly at the assembled group and bowed. "I know little Japanese, but I am please to meet you all"

"Wiltshire-san is a foreign exchange student from England, and like he said he doesn't understand much Japanese but he is learning, me and Jouro-san can both speak English so if you have any questions to ask him you can ask us to translate" Hayato said with a sheepish grin.

"Well let's get started" he turned to the circuit that lay out on the table "This is a basic circuit with a high voltage battery and a resistor of 5 ohms, this resistor could be replaced by anything such as a bulb or switch but for simplicity we are using a resistor because the resistance doesn't fluctuate very much. Now if I turn the battery on to 10 volts, the current would be 2 amps. This may not sound like much, if you touched the wire it would not injure you in any way because our skin is very resistant to electricity, and electricity prefers to take the path of least resistance." To demonstrate all three of the men touched the wire at various places around the circuit. Jouro took over at this point:

"The problem with electricity is that it likes to take the path of least resistance and if the resistor had a fault and became highly resistant then touching it may make your body the least resistant path, which is how many electrocutions happen. Although at 10 volts we are perfectly safe as long as we have skin." He explained in a soft voice that totally contrasted with his dark look.

"We deal with electrics all the time so we wear rubber soled shoes to insulate us in case of failures in the circuits" Chris chipped in, earning a few smiles and titters from the audience for his pronunciation of words. Hayato took over seamlessly;

"Exactly, and to demonstrate this I'll turn battery up to 40 volts which is enough to get through the skin, but our rubber soled shoes will protect us" Hayato turned the battery up and then turned to look at his co-workers "Wiltshire-san stop that!" everyone turned to look at the foreign man as he jumped and then hissed in pain, he had been playing with a very thin wire, wrapping it around his fingers but Hayato's shout had caused him to slip and cut them. "Wiltshire-san, that's why you always get told off for doing that, the wire we use is thinner than the wires you used in England" he said, as Jouro silently handed a handkerchief to the other male with a look of resignation on his face that showed everyone that this was a common occurrence.

"Thank you Jouro-san" Chris said apologetically. Hayato shot Chris a concerned look.

"Don't touch the circuit Wiltshire-san, it doesn't matter if you have rubber soled shoes on, the electricity will go through your hand too easily and if you touch anything that's not insulated with your other hand it will go straight through your chest and stop your heart." The audience gasped and Conan frowned, he didn't like the sound of that. "I know that sounds horrible" Hayato said regretfully "But electricity is dangerous, you should all understand how dangerous it is, we have to be very careful. If you do decide to join this course you have to be ready for many lectures on personal safety." Some of the audience nodded thoughtfully.

"Right anyway" Hayato looked a little flustered but composed himself quickly and continued. "At 40 volts there is enough current to get through the skin, and with the resistor of 5 ohms the current is 8 amps, if 2 amps can stop your heart just imagine what 8 amps can do" he said, looking seriously at them. "But I can do this" he said touching the wire with one hand "A great deal of our work is making efficient circuits that are as safe as possible, as well as fixing any faults in existing circuits safely" he said. On the other side of the table Jouro moved away from Chris in case he accidently touched him, he then leaned forwards and touched the wire.

The second he touched the wire he froze, for a split second he was silent as every muscle went taunt before the screaming started. In an immediate reaction Chris jumped forward to pull him off the wire

"NO DON'T, YOU'LL GET ELECTROCUTED TOO" Hayato yelled as he ran around the table to turn off the power. He didn't speak fast enough and Chris's screams soon joined Jouro's in a horrendous harmony. Hayato shut off the power and darted around the side of the table again to the two, laying them both on the floor.

"Someone call an ambulance!" he shouted desperately as he checked the pulse of both men. "Neither are breathing" he told the woman who had pulled her phone out while everyone else looked on in various stages of shock. She nodded quickly and started to relay information to the emergency control centre "Help me" he pleaded desperately, looking at the silent audience. A few of the people cautiously moved the barrier aside and went to assist. Hayato backed away as the helpers told him they knew first aid and started CPR.

The unmistakable sounds of an ambulance and police car could be heard in the distance and Conan spared a glance at Hayato as he watched the CPR attempts but did a double take

"_Was he smirking?" _Conan thought, he watched closely as Hayato's face contorted into concern as he knelt by Jouro's feet and asked if they were okay. The helpers gave him a pitying look but didn't see what Conan did. _"He took something off the sole of Jouro's shoe, what was it?" _Conan ran through the opening of the barrier and stood beside the man who clutched the object tightly in his hand and turned to the boy.

"Boy you shouldn't be here, we need to get my friends help" Hayato told him with a strange expression on his face "…did you see what happened?" he asked. Conan nodded with his kiddy-face firmly in place.

"Will they be okay Tsuma-nii-san?" he asked, watching carefully as Hayato looked at him sympathetically.

"I don't know, I'm so sorry you had to see that." Conan started; the apology was sincere, truly sincere.

"_Does that mean that he was faking before…did he do this?" _Conan wondered, _"But he apologized to me, he was sorry that I saw it… like it was his fault that I saw…he must have done this, but how?" _Conan looked around, he'd seen the whole thing, and there must be something that was wrong with the experiment.

"Boy, will you look after these for them, I'm sure it'd make them feel better if you looked after their good luck charms" Hayato said, giving Conan three items. Conan nodded brightly

"Okay nii-san, I'll be sure to look after them really well so they can get them back when they're better" Conan said innocently before running back to Ran's side "Tsuma-Nii-san asked me to look after the other Nii-san's good luck charms until they're better" Conan told her loudly, drawing pitying looks from surrounding people who thought he didn't understand what was going on. Ran gave him an understanding look and picked him up leaning to whisper in his ear.

"Conan-kun, you only act like this during murder scenes when you don't want the suspects to think you're smart" she whispered to him quietly.

"I know Ran-neechan" he answered, "Tsuma-Nii-san gave me these" he said, holding out the items to her, the piece of wire Chris had cut his hand on and two long nails.

"You think this was intentional?" Ran asked very quietly as the paramedics rushed through, followed by the police at a more sedate pace.

"Katashi-nii-san shouldn't have been electrocuted at all, they all said that they were wearing insulated boots and Chris-nii-san was only electrocuted because he tried to pull Katashi-nii-san off the wire with a cut hand, if his hand hadn't been cut then his boots would have protected him" Conan explained quickly, Ran frowned

"But wasn't that an accident" she asked

"He made Chris-nii-san jump when he started playing with it" Conan told her as he looked at the wire, looking closer he noticed that it was much thinner than the standard wire thickness.

"That's much smaller than the recommended wires used in circuits" Ran said suddenly, Conan looked at her in surprise and she smiled "I was talking to the electrical engineer that came to re-wire the agency lights a few weeks ago and he explained about the different wires and their uses" she clarified.

"Wow Ran-nee-chan that's really good of you to remember that!" Conan said. Ran nodded as she watched Hayato being questioned.

"Conan-kun do you know where he got the nails from? He told you they were Katashi-san's good luck charms right?" Ran asked with a thoughtful expression.

"_Ran is deducing this on her own pretty well. Being with detectives and watching how the crimes are solved is rubbing off on her. By the sound of it I won't need to do a sleeping deduction show" _Conan thought with a smile.

"Yeah Ran-nee-chan, he got them off Katashi-nii-san's shoes, but I don't know why he would keep them there" Conan said, pretending to lookconfused as he studied the nails like they knew the meaning of the universe. He saw Ran smirk out of the corner of his eye, a smirk that he often wore on his own face. Ran carefully placed Conan on the ground and then bent down to his level

"When I call you over can you come and show everyone those good luck charms Conan-kun? Just like you do when dad asks you to help" Ran asked

"Of course I will, Ran-nee-chan, have you worked out what happened?"

"I think I have, just wait behind the barrier for now" she said and walked over to the officers.

"Keiji-san" Ran said to announce her presence to the officers. "This was not an accident, this was an attempted murder" she said, causing the police and paramedics alike to stare at her in shock, there was a beeping sound and the paramedics hurriedly turned back to their work of trying to stabilise the two men.

"You're Mouri Ran right? Daughter of the great sleeping Kogoro!" said a police officer. Ran nodded shortly

"I watched everything happen, and I believe that this 'accident' was the result of planning by Hayato Tsuma." She declared with a dramatic flare that mirrored Conan as his 'older self'. Murmuring broke out in the room and Ran waited for it to die down with a little smile.

"How would I have done that? It was an accident?" Hayato declared hotly.

"An accident you cultivated yourself with knowledge of your school friends habits." Ran told the room at large "you knew that Wiltshire-san liked to play with wire but the wire that he was playing with is unusually thin and when he began playing with it you shouted at him and it caused him to cut himself making it dangerous to touch the wire, even if he was wearing his insulated boots"

Also Jouro-san shouldn't have been electrocuted by touching the wire, yet he was…and Conan-kun saw you take something off the bottom of Jouro-san's shoes. Conan?" Ran looked to him and he nodded, running into the middle of the room and showing the officers the wire and two nails. "I believe that you put the metal nails through the heel of Jouro-san's shoes to negate the insulation of the rubber, so when he touched the 40 volt wire it would electrocute him." Hayato looked boldly at her, but his gaze kept flicking down to Conan in uncertainty

"But how would I know that Wiltshire-san would disregard his training and try to pull Jouro-san off the wire, which would electrocute himself because of his cut hands, it seems more like coincidence" he said, although the tone of his voice was strange, almost resigned.

"I'm sure if we asked any of his friends we could find out about Wiltshire-san's personality and if he is likely to do such a thing" Ran told him. Hayato sighed

"I'm glad you saw through my plan, Mouri-san" he said softly, sitting down the edge of the table, "I was so happy once I managed to do it, I'd been planning that for months, but that child" he motioned to Conan "looks like my late little brother…I couldn't have walked away from here with his hopeful face in my mind, you remind me too much of his happy innocence." Conan walked over to Hayato quietly

"Is that why you gave me these? So someone would figure it out?" Conan asked, holding out the items and carefully plastering a naive expression on his face. Hayato nodded.

"I-" he stopped and looked awkwardly at Conan before trying to speak without saying something that would scar such a young impressionably child "I did that because my little brother died in an 'accident' involving those two…so I returned the favour." He stopped and refused to say anymore, telling the officers he would give them the full story away from Conan, they nodded and took him away quickly, dispersing the crowd as they left.

"_I really must have looked like his brother for him to feel such shame at his own actions, maybe seeing the image of his little brother awakened his conscience to what he had done" _Conan mused as he walked to the two men that were being treated by the paramedics.

"Will they be okay?" he asked sweetly, one of them looked up from cleaning Chris

"They'll be fine" he said uncomfortably with a look of sorrow and patted Conan on the head before ushering Ran over to take him out of the room.

"You did really well Ran-nee-chan" Conan told her as he carefully slipped the items into his pocket, the police wouldn't need evidence if Hayato was freely confessing. Ran smiled at him

"Now I understand why dad and Shinichi do this, it gives the victims a voice and they can rest in peace" Ran said quietly. Conan didn't believe in the afterlife but he agreed with her sentiment, he liked it more for the bringing of justice than the spiritual aspects. But Ran had always believed, and that's why she was able to send Hayato to prison without remorse.

"Shall we check out the Criminology degrees?" Ran asked Conan with a little smile.

"Yeah sure Ran-nee-chan"

**A/N: Less physics word and equations in this one but the conduction and insulation parts were all physics, I was just less obvious about them. Electricity is difficult to write about because some of the parts we learn about in physics have no practical application in the story (like electron drift velocity, which is to do with electrics but has no applicable meaning here and I couldn't just drop it in randomly). Hope you enjoyed it and that it made sense. I hope you look forward to my next physics one shot which will likely be about turning moments. ^.^ **


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